The Tribesmen are the descendants of Corsair Raiders who settled the Coast of the Sea of Núrnen after the armies of Gondor withdrew hundreds of years ago. In her youth, Lady Marwen was a respected and feared warrior throughout the Southern region of Mordor before she settled down to lead her people. Since the return of Sauron and the Black Captains she has been searching for any means to hold back the dark tide of war.
Events of Shadow of Mordor
When Marwen sought the aid of Saruman regarding the threat of Sauron, she became possessed by him and sent her daughter, Lithariel, to find Celebrimbor. She uses prophetic powers to guide Talion and Celebrimbor to one of Celebrimbor's relics. She advises them to use Celebrimbor's powers to take control of an army of Uruks, and use them to lead an assault against Sauron.
Talion realized that Marwen was possessed, resulting in Saruman's attempt to remove Celebrimbor from Talion's body. Lithariel frees her from his possession by breaking the staff, saving Talion and Celebrimbor. However, Talion still carries out Saruman's plan, and leads his army of mind-controlled orcs in an assault against the Black Hand's stronghold at Ered Glamhoth.
As the Black Hand of Sauron later attacks Nurnen and leaves smoking ruins in his wake, it is assumed that Lady Marwen and Lithariel were forced to flee, were captured or killed in the resulting attack.
- The name Marwen likely means "Dwelling maiden" in Quenyan (from mar = "dwell, abide" and -wen = "maiden"), a reference to her being confined to her home for much of the game.